Inductively Coupled RF Discharges Using Helical Antennas(Physics, Process, Instruments & Measurements)

Presented in this paper are experimental investigations on the radio frequency (rf) discharges at 13.56MHz using helical antennas with different pitches and azimuthal mode numbers. Obvious transition of the discharge has been observed in the plasmas produced using the antenna with an azimuthal mode number of m=±1 in presence of external mirror field>500G with rf power>350W. The transition of the discharge mode has been accompanied with the significant decrease of the rf circuit current indicating the drastic change of the plasma loading due to the increase in the plasma density.